IMPROPER SMOG OR FRAUD?

2000 Infiniti I30 • 173,280 miles

Oct 12 2011 I purchase this car in drive test car is ok but few drives after less than 50 miles check engine light is on dealer offer to " fix it" nd light clear off but less than 50 miles light came back on I had the car inspected and tested by smog technician and confirm car fails to pass smog test (oct 17/11)and had smog problems this was with less than 400 miles the car got 173280 miles when fail smog test nd got 172913 from previous smog (agust 20 /11) and less of 90 days, the smog technician said the car mechanical smog system is not ok, but in document it is, please tell what you think yor answer is very important.

I need to know what part of the emission system is setting a code. Also, if you purchased it from a dealer and it won't pass inspection, you need to check your state's laws for such things. Here in PA, if it is sold, it has to be inspected and the purchaser needs to be made aware of any issues, and this would be one.